Membership and participation in Radiation Therapy Oncology Group studies is essential if the results of radiotherapy or radiotherapy in combination with other modalities are to be improved. Although pilot studies in either chemotherapy and radiation, hyperthermia and radiation or radiation sensitizers or protectors in radiation can be undertaken by individual institutions to test the toxicity of successful combined modality treatment developed in laboratories, it is impossible for any one institution in the United States to institute and complete randomized clinical studies to confirm or to reject significant results obtained in the laboratory. Although the use of radiation and chemotherapy or radiation and surgery or a combination of all three is being tested either as adjuvants or primary modality treatment in randomized trials by cooperative groups other than RTOG; RTOG is the only current cooperative group which has the ability to develop combined modality hyperthermia protocols.